Chapter 1, Introduction to XML Forms Architecture (XFA)
XFA Specification
Major Components of an XFA Form: XFA Template and Data
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XML Data Package (XDP)
XDP provides a mechanism for packaging units of form-related expressions within a surrounding XML
container. Such form-related expressions may include some or all of the subelements illustrated on
page 16.
Such subelements include the XFA template, PDF objects, XFA data and the data schema, custom
XFA-related form content, and XML.
Packaging form-related content within an XML container may be important for XML-based applications
that produce or consume XFA form content.
An XFA processing application may produce an XDP document when it submits a form (or a form’s data) to
a server or when web services are activated.
When in XDP form an XFA document may be validated using the schemas which are attached to this
specification. See
“Schemas” on page 979
PDF Document
XFA may be included as an object in a PDF document, mirroring the structure illustrated on
page 17.
All
XFA subelements are included in such a PDF document.
Major Components of an XFA Form: XFA Template and Data
This section provides a high-level description of the major components of an XFA form, which are XFA
template and the data provided by a user or by a server.
XFA distinguishes between template and data. The template defines presentation, calculations and
interaction rules. Content is customer's application data. Though they are often packaged together,
template and content are separate entities.
XFA Template
XFA template is the XFA subelement that describes the appearance and interactive characteristics of an
interactive form. It was designed from the ground up to be an XML-based template language.
XFA follows a declarative model in which elements in an XFA template describe the components of the
form. That is, XFA template does not include procedures that draw the objects on a form.
About XFA Template
Most people are consumers of forms, rather than producers or designers of forms. Yet, in order for a
software product to utilize forms, someone first had to expend a degree of thought and work towards the
act of creating a form. This specification is focused on the task of form creation, and it is important to
distinguish between the “form” that the creator designs, and the “form” that a consumer handles — they
both represent the same form, but at two very different stages in the form's life-cycle. XFA clearly
distinguishes between the two stages via the following terminology:
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Form — what a person filling out a form works with, which is given life by an XFA processing
application such as Acrobat.
Template — what the form designer creates, which represents the potential for a form. A template is a
collection of related subforms and processing rules.
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